run.py

   1 #!/usr/bin/python3
   2 """
   3 PyAudio example: Record a few seconds of audio and save to a WAVE
   4 file.
   5 """
   6
   7 import os
   8 import pyaudio
   9 import wave
  10 import sys
  11 import struct
  12
  13 DEVICE = 3  # which alsa decive to read
  14 CHUNK = 1024  # how many bytes at a time?
  15 FORMAT = pyaudio.paInt16  # Format
  16 RATE = 44100
  17 RECORD_SECONDS = 0.5
  18
  19 VOLUME_CONSTANT = 11.975454545454545
  20
  21 p = pyaudio.PyAudio()
  22
  23 stream = p.open(format=FORMAT,
  24                 channels=1,  # Our ampmeter always returns 0 on the second channel
  25                 rate=RATE,
  26                 input=True,
  27                 input_device_index=DEVICE,
  28                 frames_per_buffer=CHUNK)
  29
  30 while(True):
  31     total = 0
  32     for i in range(0, int(RATE * RECORD_SECONDS / CHUNK)):
  33         data = stream.read(CHUNK, exception_on_overflow=False)
  34         values = struct.unpack('h'*CHUNK, data)
  35         #print(values)
  36         chunk_total = 0
  37         for value in values:
  38             if value > 0:
  39                 chunk_total += value
  40             else:
  41                 chunk_total -= value
  42         chunk_total /= len(values)
  43         #print(chunk_total)
  44         total += chunk_total
  45     avg = total / int(RATE * RECORD_SECONDS / CHUNK)
  46     watts = avg / VOLUME_CONSTANT
  47     print("average {:.0f}W".format(watts))
  48     os.system("rrdtool update power.rrd N:{:.0f}".format(watts))
  49
  50 stream.stop_stream()
  51 stream.close()
  52 p.terminate()
  53